The overall aim of the research outlined in this proposal is to achieve a better understanding of mental retardation and of methods for ameliorating some of the problems characteristic of the mentally impaired. As retardation is defined mainly in terms of cognitive functioning, we are primarily concerned with cognitive processes; however, we recognize that other aspects of performance are involved in the overall syndrome, and we also devote some effort to aspects of social functioning. Our aims are then to elaborate a theory-based definition of retardation which will implicate areas in which retarded children have particular problems, and then having identified such areas, investigate the development of training techniques designed to overcome the shortcomings. Research at several levels of this scheme is proposed. Several projects are concerned with the last step, the training of cognitive skills, and modifying attribution tendencies is also included. In all the training research, the major goal is to achieve generalization of the target behavior to novel situations. A number of other projects are addressed to the question of locating further sources of individual differences and thus contributing new information about the characteristics of retarded individuals. Included here are programs involving physiological indices of attention, measures of speed of processing, and aspects of motor development. Finally, understanding of aberrant development also requires an adequate description of normal development. Where extremely young children are involved, there is relatively little known about even this. Several projects are addressed to filling in this void, and also emphasize the delineation of early precursors and indicators of retardation. This work, dealing with children prenatally and through approximately age four, can be described as working toward a battery of items which could be used in the early detection of retardation. Areas of inquiry here include the development of concept formation capabilities, general self-regulation skills, and patterns of parent-infant interaction.